Apparatus for controlling treatment of hydrocarbon oils



Aug. 24, 1937. nrc. PowELL Er AL j 2,090,915A

APPARATUS FOR CONTROLL'ING TREA'I'IENT 0F HYDRQCARBOH OILS rmdnov. 23. 1933- Poiooiool Ang. 24, i937 UNITED sTATEs PATENT oFFicE manil'rus' ron coN'raoLuNG 'ramirm'r or maocAanoN oms nono. Powell, roi-ooi mus, and mollo E. Priester,

N York, N. Y., alaignors to AThe Texas Company, New York, N, Y., a corporation of Delaappuoniion novemberzs, im, sonni No. sessies s china. Y (ci. 19e-132) 10 thereof, it is essential that the type of stock used should be carefully selected, In the cracking of hydrocarbon oils. for instance, it is desirable to subject oil to high temperatures which may result in detrimental coke if care is not exercised 15 in selecting or producing in the process an exceptionallyclean stock to be subjected to said high temperatures. In the so-called vapor phase cracking processes, the oil being introduced into the heating zone is subjected to relatively high temperatures, while optionally being maintained under superatmospheric pressure. in order to produce gasoline of high anti-knock quality. lIi' a clean oil is not used in such a treatment objectionable coke is 25 deposited in the heating zone whichobviously furthermore decreases, fect ofthe deposited cok may be imparted to the oil.

This invention is particularly adapted to auto- 30 mailoolly oonirouing che cleanliness ofthe oil I being passed through the heating sone.

due to the insulating ef- An object vof the invention is to provide aprocess of` automatically controlling the clean- Y n liness of the oil bein'g'introduced into the system. "1. Another object of the invention is to provide a process in which the cleanliness of the cycle condensate produced in a cracking operation is automatically controlled by variations in the color thereof.

A further object of the invention is to provide a process. in which variations in the color of the cycle condensate produced in a cracking operation automatically actuittes adjusting mech- 5 anisin for .correcting said change` in -coiorto .thereby control the cleanliness of the vcycle condensate. by restoring the oil to its desired color. Stili another object of therinventlonl is to f provide an apparatus suitable for carryingV out 5.3 the process.

'wiiniliese'ind other obieots ln view, 'which may bedncident to the improvements, the invenl tion consistsinthe-several method steps and the partsand combinations-'to be hereinafter set 55 forth and claimed, with they understanding that shortens the length of any one operation and.

,the maximum heat that the manner of carrying out the invention may be varledwithout departing from the spirit and scope of the appendedclaims.

In accordance with the invention the color of the oil being treated lis used as a criterion of the cleanliness thereof. It has been found thatvariations in the color of the oil correspondingly indicate variations of its'cleanliness. lIn prac' ticing my invention the color variations may be detected prior4 to any substantial change in color of thela'rge body of oil being used and the necessary changes in operation automatically effected to prevent any substantial variations in the cleanliness of the oilfrom that'desired.

In carrying out the invention when .applied to a cracking operation, asample of the vapors passing to the fractionating zone may be withdrawn, condensed and passed through a suitable sight glass. The oil passing through the sight glass is generally light in color and permits the passagevof light rays therethrough. A suitable apparatus, which has been calibrated with respect -to a standard color, may be associated with the sight glass in such a manner that any vvariations in the color of the condensed sample will automatically actuate suitable control mech anism for accomplishing the necessary changes` inoperating conditions to thereby correct against any changes in the cleanliness of the cycle condensate. It has been found that variations in .the color of the cycle condensate may be readily detected and corrected by employing a photoelectric cell arrangement which, due to its sensitiveness, readily eifects the necessary changes in operating conditions to maintain the cycle condensate of the desired cleanliness.

`In order to make the invention more clearly understood, there is shown in the accompanying drawins. means for carrying the same into practicaleiiect without limitingthe improvements in their useful applications to the particular cons tructions which, for the purpose of explanatiom have been made the subject of illustration.

Figure l is a diagrammatic .elevational view of an'apparatusy suitable for carrying out my invention.

Figure 2-is'a view of an electrical wiring dia- .gram associated with the sight glass for carrying out theinvention.

'Ihe invention is to be illustrated as applied to thecrackingof" hydrocarhonoils, but it will be readily understood from the detailed description thereof that it is not limitedto the cracking of oils but has other applications in the petroleum art.

Referring to Figure 1, there is shown a furnace I having a heating coil 2 positioned therein. 'I he' furnace I may he heated by suitable burners 3..-

An enlarged reaction chamber is designated by the numeral 4, a suitable dephlegmating. zori'e,

such as a fractionating tower, isdesignated by l While a particular type of cracking apparatus f has been shown, itis to be clearlyv understood that this is merely for illustrative purposes and any type may be employed.

The fresh charge, whichmay be in the nature A of a reduced crudeor a heavy gas oil, may beforced through a suitable inlet linea by means of a pump 9 into the upper portion of the reaction-chamber Q. The reaction chamber may be provided with suitable balfle plates -orbubble trays Il for the purpose of assisting in a preliminary fractionation of the vapors resulting in the enlarged chamber t as willbe hereinafter err- I plained. The fresh charge, which may be preheated, if desired, introduced into the reaction chamber c, is contacted with highly heated upwardly rising vapors, the formation of which will be later explained, thereby imparting heat to the fresh charge to accomplish distillation thereof.

` The vapors resulting from the fresh charge to- 30 gether with'the highlyl cracked vapors resulting from the heat treatment of oil passing through the coil 2 are conducted through a line I2 into the lower portion of the bubble tower 5. Unva-i porized constituents of the oil collected in the bottom of the reaction chamber Il, which may be i.nthe nature of a fuel oil, may be withdrawn through a valved line I3 and conducted to stor-l '50 liquid resulting fromthe condenser-6 may be Y passed'through a' line I5 to the gasoline distillate receiver II which may be provided with a valved gas outlet I@ and a valved liquid drawoi Il. a. The reflux condensate formed in the lower portion of the bubble tower 5 as the result of fractionation therein, in accordance with my invention, is a-condensate of any desired color suit' able to be recycled -to the heating coil 2 wherein 6o it may be raised to a high cracking temperature.

The reux condensate `may be withdrawn from the bubble towerl 5 through a valved line I8 and forced by means of a pump I9 through the heating coil 2. The condensatebeing `forced through the heating. coil 2 may be subjected tocracking conditions at a high crack per pass and as a result of the cleanliness of the oil, detrimental coke deposition is,prevented. T he highly heated oil from the heating coil 2 may be passed through a line' ZI into the reaction chamber d wherein "it is digested in the vapor phase. If desired, a-

preliminary digestion or soaking of the oil may befaccomplished by providing an additional coil suitably. positioned within the furnace I. means of a'. pressure reduction valve 22 positioned in the line 2|, a diierential pressure may,vii' desired, be maintained between the heating coll 2 and the reaction chamber 4. v

The upwardly rising cracked vapors in th reaction.' chamber 4 contact the downwardly nowing fresh charge thereby imparting heat thereto to strip lighter constituents therefrom. The vapors in the reaction' chamber d may be suitablyrefluxed by introducing a portion of the redux condensate formed in the bubble tower 5 into the reaction chamber d. As shown, a portion ofcthe reflux condensate may be forced 'through the line 23 by means of a pump 2li into the upper portion of the reaction chamber i. If desired, the reflux may be cooled before entering the chamber d. It will be readily understood that by passing the upwardly rising v4vapors in ,the reaction chamber 'l through the baies or bubble trays II and in addition introducing a reiiuxing medium into them, objectionable heavier ends of the vapors are removed.

My inventionis particularly adapted to the control of the ,color of the cycle condensate col- `lected in the lower portion of the bubble tower 5. The `cycleL condensate collected in the lower portion of the bubble tower 5 forms in a relatively large body and any change in color, which is used as a criterion of the cleanliness of the stock, is very gradual and may become objectionable.

In accordance with my invention, the colorl of the,

sate introduced into the upper'portion of the t reaction chamber ll removes or knocks ba'ck heavy undesirable constituents from the vapors. By regulating the quantity of the reiluxing medium ybeing introduced through the line 23, excellent control of the cleanliness of the cycle condensate.

maybe obtained. It is to be understood that my invention is not limited to reuxing a part of the condensate as illustrated in the drawing, as other reuxing mediums extraneous to those produced in the system may be satisfactorily employed.

In carrying out my invention as exemplified by the drawing, a sample of the vapors and any liquid that may be vpresent passing through the vapor line I2 may be withdrawn through a small branch line 25 preferably branched from a lower portion of the vapor line 12. The sample with- I drawn may be passed to a suitable condenser 2' wherein it is condensed. The `liquid oil resulting color of the condensed sample will be detected and the necessary change in the quantityl of reuxing medium being introduced into the reac tion chamber tautomatically controlled. The electrical arrangement may comprise a source of light 28, a photo-electriccell 29, a suitable control mechanism 3|, a motor 32 and a motor operated valve 33. The source of light 28 may beenergized llow from the photo-electric cell to actuate the control mechanism 3l. When there are any variations in the color of the oil or other characteristics, to effect the transmitted light, thecur- 5 rent produced by the cell 23 will vary proportionately to the variationsof the characteristics of the oil which eifects the light beams passing from the source of light A28 through the sample of oil to the photo-electric cell 23,. The current l0 thus produced is conducted to the controller 3l which vmay be of am suitable type, such for example, as suitable relays for opening and closing the circuit. The controllerl may likewise.

be connected to a suitable power supply, not

shown, for supplying the necessary electrical energy thereto. Depending on the change in the oil passing through thesight glass 21, the controller 3i will close alcirc'uit therein for starting the motor 32 in one direction or the other. The motor 32 may be connected to a suitable power operated valve 33 which may be positioned in a steamV line 34 connected to the pump 24 for introducing steam thereinto to actuate it.

The motor will thus open or close the valve 33 thereby forcing more or less steam into the pump 24 which in turn forces more or less reuxing medium into the chamber 4 as the case may be. It will be appreciated from the above that any variations in the color or other characteristics of the sample passing through the sight glass 21 will automatically be compensated and controlled by varying-the amount of reflux through the operation of the pump 2l.

It may be desirable to maintain the latest valve 5'setting on the pump24 afterV actuation of the control arrangement for a period long enough for any change produced in the color of the cycle' condensate to become evident in the sight glass 21. The sample being passed through the sight f1 0 glass 2,1 may be of varying color which may result in too many changes of the valve setting. This will result in varying amounts of reflux being introduced`V into the reaction chamber 4 before the eifect produced by the original change of l5 reiiuxing becomes evident. Inorder to avoid this possible hunting ofthe motor foi the correct valve setting to control the amount of reflux; a suitable interrupter switch 35 may be interposed in the circuit between the controller 3l and the motor 32. The interrupter may be set to interrupt the current passing through the motor for a period suiliciently long for the eilectprod'uced by the original change in the reflux rate to become evident in the sight glass 21. IfV the correct amount of reflux is not being forced into the reaction chamber 4 after` the first adjustment, the' motor 32 will be again actuated .when the interrupter closes the circuit thereby forcing more or less reflux, as the case may be, into the reaction chamber in order to obtain the desired clean vaporA fraction therefrom.

The operation of the invention from the foregoing will be apparent to those skilled in the art.

.m per pass while Ytherethrough.'will vary depending on the oil being treated. 'I'he color may for instancebe between 5 and 30 on a l" Lovibond scale. In accordance with the inventionathe color Vmay be controlled between any 75 ranges and it has been found that excellent con- Y Y 3 trol may for instance be hadbetween say, I4 and I C.

In Figure 2we have shown more in rieten an electrical arrangement that may be used for automatically controlling the colo; of the cycle condensate.

shown a. pair of photo-electric cells 36 and 31, a' 'source of light 38 and a sightI glass 33 for passing f the sample of condensed vapors therethrough.

Referring to this ligure, there is 'I'he photo-electric cells are connected in opposition, that is, the anode of one is connected to shown is conducted from s; suitable source such as a commercial lighting circuit or batteries by Y conductors 42 to a suitable transformer 43. Thetransformer may be of any desired type suitable for producing the desired voltage.

suitably connected to the circuit of the photoelectric cells is an amplifying tube 44. The necessary Vvoltage for the source of light 38 and the amplifying tube 44 may be supplied through branch leads from the conductors 42, as illustrated, the voltage to the lilameneof the amplifying tube 44 being stepped down to that desired by means of the transformer 45.

The plate circuit of the amplifying tube 44 is connected to a suitable controller indicated generally by the numeral 46. The controller 46 may comprise a d eection galvanometer 41, such as a milliammeter, suitably connected to the grid circuit of .the amplifying tube 44 and to the transformer 43 by means of a conductor 4D, thereby completing the circuit through the photoelectric cells, a plurality of contact points 48 of a relay and a motor operated contactor 49, The

motor operated contactor 49Y may be suitably connected to the galvanometer 41 in order that it will close one set of the contact points 48 depending on the deection of the needle of the galvanometer 41. The motor operated contactor 43 may be of the type adapted to close either -pair of the contact points 48 at desired intervals.

The controller 46 may be connected to a motor operated valve indicated generally by the numeral 5i. 'I'he motor operated valve may comprise a reversible motor 52, having fields 53 and 54 wound in the opposite direction to provide a split eld time has elapsed for any change in color produced by the change in the refluxing rate to become evident in the sight glass. V'Al'herinterrupter 51 may comprise a motor 58, having a suitable means asociated therewith, such as a cam 59, for

the cathode of the other. 'I'he photo-electric cell i closing a'pair of contacts Sito complete the circuitftherethrough at specied intervals of time.

' The motor 43 of the controller 46 and the motor 58 of the interrupter 51 may be synchronized in order that closing' of either of contacts 48, effected by operation of the motor 49, will simultaneously occur when the contacts 5l are closed by operation of the motor. In this manner the electrical circuit is completed when any changes tions in the current will occur.l By adjusting a] resistance 62 connected in the plate circuit of the amplifying tube 44 a zero setting may be obtained for the galvanometer 4l. 'Ihis zero setting will be maintained. as long as the color of v the oil passing through the sight glass 39 does not vary beyond predetermined limits.

Explaining now the operation of the arrange-y ment shown inFi'gure 2, we will assume that the 15 color of the oil passing through the sight glass 39 has become too dark, lwhich would indicate that an insufficient quantity of reux was being inltroducecl into the chamber 4 thereby permitting the return of reflux condensate tothe heating coil 2 of not the desired cleanliness. This change in color would -aiect the'light being transmitted to the oil passing through the sight glass 39 from the source of light 38 thereby setting up pulsations or currents in the cell 3l proportional to the color change. Thesevpulsations or Vcurrents passingthrough the amplifying tube M are amplified and are then conducted to the galvanometer di through the grid circuit including the resistance 62. The amplified pulsations or currents will cause the deflection of the galvanometer needle thereby, through cooperation with the motor $9, establishing contact between the pair of contacts 3S which are closed when more reflux is to be pumped into the chamber t. The contacts d8 are supplied with electrical energy from one of the conductors'liZ through a conductor 63 to the closed contacts d8, thence to contacts 55 which are closed by the current passing through a conductor 6d. The current will then pass through 40 the closed contacts 55 to the iield 53 thereby causing the motor 52 to rotate in the desired directon for opening the valve 56 suitably con-4 nected thereto. By opening the valve 56 more steam is admitted to the pump 2li thereby increasing its speed for forcing additional. reux into the chamber 6l. The electrical circuit is cornpleted through a conductor 65 connected to the contact tl of the interrupter 5l. As before described, the contacts Si are closed by the cam 59,

associated with the motor 5t, simultaneously with the closing .of one pair of the contacts 33. The

A current passing through the contact 6l is then conducted to one of the branch leads from the conductors i2 as shown.

- If the color of the oil passing through the sight glass 39 becomes too light, pulsations or currents will set up thereby deflecting the needle of the galvanometer in the opposite direction. When this condition exists,'the pair of contacts dt and 55 shown as opened in Figure 2, will be closed, the

' other contacts de and t5 being opened, and the field 5d will become energized through the closed contacts 55 thereby causing the motor 52 to rotate in a direction opposite to that just described. 'In this manner less steam will be forced into the pump 2d by thev closing of the valve 5d. The electrical circuit under these conditions from the motor 52 is completed as already described.

It is to be clearly understood that the neces? sary equipment for carrying out my invention --.gmaybevariedand any well known Iequipment smployed. f Wfhile a particular circuit arrange- 'menthasebeen-illustrated, it will be appreciated jui/ that-'variations therein may be made by those 'f 75 skilled-fijnT-fthe art without departing from lthe scope`of the invention.. I-f desired, the'entire .electrical arrangement illustrated may be assembled as a compact unit and located at the desired point in theireiinery.

It is also within the scope of the invention to 5 have a suitable automatic recorder associated with the electrical arrangement described for the purpose of automatically recording color variations. c

`whii'e the invention has been described 1n con- 1o` nection with changing the rate of reux tc the tower 4, it is to be clearly understood that it is also applicable to many otheruses. 1For instance,

' in any,A type of cracking operation involving considerable equipment prior to the final fractional5 tion of the cracking vapors, it is possible to 'vary the reux rate into the vessel preceding the final fractionator. It will also bev apparent that in addition to or together with varying the reiiux rate being introduced into the primary fractiona- 20 tor, the rate of /firing of the burners 3 and/or the rate of ow through the coil d maybe varied in accordance with my invention in order to clean up the reduit condensate being' returned to the cracking system. 25 y raised to a cracking temperature of from 800 F. 30T

to 1100 F. The cracked products at the elevated temperature vmay then be introduced into the reaction chamber d optionally'operated by al reduced pressure, if desired, and the upwardlyrising vapors contacted by the vdownwardly flowing "35 fresh charge. The highly heated vapors impart. heat to the fresh charge thereby stripping lighter constituents therefrom. A suitable refiuxirig medium? such as reflux condensate formed in the system, is introduced through the line Y23 by 4o means of the pump 2d to knock back any unf desirable heavy constituents of the upwardly rising vapors in the chamber l.. The vapors of the desired cleanliness are conducted A`through the line i2 and introduced into the lower portion of 45 the bubble tower 5 wherein they are fractionated to produce a reflux condensate and an overhead vapor fraction of the desired end point.

In controlling the color of the reflux condensate being formed in the lower portion of the bubble l.'30 tower 5, a sample of the vapors and any condensed liquid passing through the line l2 is withdrawn through the line 25, condensed and passed through the sight glass 2l. If the color of the condensed sample passing through the sight glass 55' 2l is satisfactory no variations will be set up in forcing more or less reflux through the line 23.

In this manner a quick indication of the reflux condensate going/on' color is possible and the 65 necessary changes to restore the color of the reux to that desired are automatically made. It will be apparent that before any appreciable change in color of the reflux takes place within "the bubble towerl 5, the necessary prior warning 7a with its resultant correction has taken place.

For example, reflux conde sate having a color of between 5 and 3G on a,1/ Lovibond cell may satisfactorily be returned tothe cracking colland therein subjected to high cracking conditions of temperature and pressure. The photo-electric cell arrangement disclosed has been found to be satisfactory in detecting slight variations in color v and any desiredcolor of the oil may be controlled and maintained in accordance with the invention. If an-oil having a color of 15 .ona V2" Lovibond cell is desired, the invention is adapted to automatically correct any variations fromthat color, thereby resulting in excellent control of' the cleanliness of the oil being treated.

It has been found, as before mentioned, that the color of the reflux'. condensate being introduced into the cracking zone will v ary depending on' the nature of the charging stock. A straw colored reflux condensate has beenfoundto be generally satisfactory and particularly oneV having a green cast. Generally when the oil becomes dark, such as having a brown cast, the cleanliness thereof is notjsatisfactory and the necessary changes are made to produce the desired lighter color. These colors are merely examples and should not be construed as being restrictive of the scope of the invention.

From the foregoing, it will be apparent that thel invention is not limited to the ,control of operating conditions of a cracking operation. It is Within the scope of the invention to control the cleanliness of any oil being treated. For instance, in the production of lubricating oils, the stock being treated is introduced into a treating chamber filled with contact material. The quantity'of-oil being introduced depends on the cleanliness thereof and the invention is readily applicable to autoriiatically control the rate of feed of the oil toV the treating chamber when the color thereof varies .from predetermined limits.

Whileb there has been shown and described thev lpreferred embodiment of the invention, it is to be .understood that the invention is not confinedto the precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein,by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

what we claim is:

1. In combination with an oil cracking unit whereinoii is subjected to cracking, the cracked products separated into vapors and residue, the vapors fractionated in primary and secondary fractionating zones and the secondary condensate formed in the secondary fractionating zone' returned to the cracking unit for furtherv cracking treatment, an apparatusl for regulating the opacity of the secondarycondensate which comprises regulatable means for introducing variable amounts of cooling uid Vinto saidpri mary fractionating zone, means for separately;

condensing a. portion of vapors -from said primary fractionating zone to, said secondary fractionating zone, `means responsive to the opacity of the condensate formed by separatelyy condensing said portion of vapors'for regulating the amount of cooling iiuid introduced-into said primary fractionating zone and means interrupting the operation of said last named regulating means for a' predetermined time interval to pera',ooo,915 v mit the changed condition *of the vapors leaving Y( the primary fractionating zone, effected by the changed' amount oi'- cooling fluid introduced thereinto, to be determined byv said means rel sponsive to the opacity of the condensed Portion of the changed vapors prior to further regulation e of said regulating means.

2. In combination with an oil vcrackingf'unit wherein oil is subjected to cracking, Vthe cracked products separated into vapors and residue, the' vapors fractionatedin primary and secondary -fractionating zones and the secondary condensate formed in the secondary fractionating zone returned to the cracking unit for further 'cracking treatment, and apparatus for regulating. theopacity of the secondary condensate which comprises regulatable means for introducingvariable amounts of cooling fluid intovsaid primary fractionating zone, means for separately 'condensing a portion of vapors passing from said primary fractionating vzone to said secondary fractionatopacity of the condensed portion'of the changedv vapors prior to further regulation of said regulating means.

3. In combination with an oil crackingunit wherein oil is subjected to cracking, the cracked products separated into vapors andv residue -and the vapors fractionated in primary and secondary fractionating zones, an apparatus which comprises means for returning'a part'of the secondary condensate formed'in the secondary f ractionating zone to the cracking 'operation forfurther treatment, regulatable means for introducing another part of said secondary condensate into said primary fractionating zone as reuxing medium, means for separately condensing aportion of vapors passing from said primary-.fractionating zoneA to said secondary fractionating zone, means .responsive to the -opacity of the 'condensed portion of the vapors for regulating the quantity of said secondary condensateintroduced into said primary fractionating zone, and means interruptingthe operation of said last "named means for a predetermined time interval f 'to permit the changedcondition lof the Vvapors leaving the primaryfractionating zone, effected by thechanged quantity of said secondary'.con-y densate introduced thereinto,v to be determined .by said means responsive to theopacity ofthe j I condensed portion of the' changed vapors prior' to furtherregulation of said'regulating means.`

LESLIE E. Pams'rna'. 

